1. Field of the Invention
The present invention relates to a system and method for automating the process of conducting psychophysics experiments. More specifically, a system and method for conducting the multidimensional scaling method for psychophysics.
2. Description of the Related Art
Psychophysics is commonly defined as the quantitative branch of the study of perception, examining the relations between observed stimuli and responses and the reasons for those relations. Since its inception, psychophysics has been based on the assumption that the human perceptual system is a measuring instrument yielding results (experiences, judgments, responses) that may be systematically analyzed.
Because of its long history, its experimental methods, data analyses, and models of underlying perceptual and cognitive processes have reached a high level of refinement. For this reason, many techniques originally developed in psychophysics have been used to unravel problems in learning, memory, attitude measurement, and social psychology.
In the general paradigm of visual psychophysics, a human subject is presented with accurately controlled stimuli, and in certain prescribed ways, is asked what he sees. From the results of these experiments, inferences can be made about the nature of visual processes.
In the printing industry, visual psychophysics testing can be used to determine correlations of human perceptions of print quality with physical measurements such as, for example, gray levels, halftone screening, density control, and the like. Psychophysics testing methods which have been used in the printing and other display industries include the Paired Comparison, Ranking Order, Rating Scales, Ratio Scales, Categorical Scales, Multidimensional Scaling methods. The above methods themselves and their statistical analysis are fully described in James Bartleson and Franc Grum, xe2x80x9cVisual Measurementsxe2x80x9d, which is Volume 5 in xe2x80x9cOptical Radiation Measurementsxe2x80x9d, Academic, Orlando, 1984; and J. P. Guilford, xe2x80x9cPsychometric Methods,xe2x80x9d McGraw-Hill, 2nd Edition, 1954, which publications are incorporated herein by reference in their entirety.
Multidimensional Scaling (xe2x80x9cMDSxe2x80x9d) method involves identifying relative similarity and differences between a group of three samples. The observer is asked to determine which two samples have the most differences and which two samples have the least differences. A determination of which factors make the most difference in sample quality can be determined from the MDS method.
The process of conducting a psychophysics experiment is time and labor intensive. It involves the generation of the samples to be observed, the randomization of the samples, the observation of the samples by the test subjects, the collection of the observation data, and the statistical analysis of the data. Many experiments require 15 to 20 or more observers to view the samples. Thus an experimenter""s job would involve generating the samples, randomizing the samples for each of the 15-20 observers, collecting the data during each of the 15-20 observation sessions, and conducting the statistical data analysis by hand.
Because of the time and labor intensive nature of this testing, there is a need to automate the process, thereby greatly reducing the testing time.
To overcome the limitations in the prior art described above, preferred embodiments disclose a method, system, and program for comparing multiple factors using multidimensional scaling analysis. Sample sets are generated where each sample in the sample set is created by a different algorithm made up of at least three factors. Relative differences between the samples in the sample set is observed and recorded. Statistical analysis is then performed on the observed differences between the samples in the sample set, and the results of the analysis are displayed as plots.
In preferred embodiments, a displayable test building window, which includes input fields to receive input on at least one observable sample set, is used to set up the observation and recording process. A data gathering window is generated containing at least one perception input field for each observable sample set. The observer is capable of entering perception information in each input field concerning the observable samples. Observer perception input on the observable samples is received and stored.
Preferred embodiments provide an improved method and apparatus for testing definition and generation for multidimensional scaling using a GUI program for graphically specifying data items and computations to be performed on the data. The present invention provides a psychophysics testing tool that uses objects to define both testing layout and the data aspects of the testing. Unlike the prior art, the present invention provides a graphical way to accomplish both of these testing aspects. That is, a GUI program is used to facilitate all testing steps, including sample generation, randomization, observation, data collection, and analysis.